The meltemi: sailing the Aegean’s summer wind
The strong north wind of the Aegean summer decides most cruising plans in Greece and Turkey from June to September. Where it blows hardest, when it lets up, and how we plan around it.
In this piece
- What causes the meltemi wind
- Meltemi season: when it blows
- Meltemi direction around the Aegean
- How strong the meltemi blows, and when in the day
- Acceleration zones and gusts off the islands
- Sailing Greece in the meltemi: planning passages
- Anchorages and harbours in a meltemi
- What the forecasts get right, and what they miss
- Planning a week in high summer
The meltemi is the strong, dry wind that blows across the Aegean in summer. It sets in around May or June, is at its strongest in July and August, and fades through September. It usually blows force 5 to 7, sometimes 8, and often for several days at a time. It comes from the northeast in the north Aegean, from the north through the Cyclades, and from the northwest along the Dodecanese and the Turkish coast, where it is called the meltem.
It is also a large part of why the Aegean is such good sailing. It blows from a known direction under a clear sky, it keeps the summer heat bearable, and if your route runs south with it you get fast reaches day after day. Plan against it and you spend your holiday beating into a short, steep sea and watching the boats going the other way.
These are our home waters, and almost every plan we make between June and September starts from the same question: where will the meltemi let us go this week?
What causes the meltemi wind
The ancient Greeks called these the etesian winds, the annual winds, because they come back every summer. The cause is a pressure difference on a very large scale. In summer, high pressure sits over the Balkans and central Europe, while a broad area of low pressure, built by the heat, lies over Turkey and the Middle East. Air flows from the high toward the low, and the Aegean, a long sea running north to south between the mountains of Greece and Anatolia, is the gap it pours through.
The stronger the high to the north and the deeper the low to the east, the harder it blows. That is why the meltemi comes in episodes: a few days of force 6 or 7 while the pattern holds, then a day or two of lighter wind when the high weakens or shifts, then the next round. The air has come a long way over land and is sinking as it arrives, which keeps it dry and gives meltemi days their hard blue sky and long visibility. You can see the next island clearly, and it is further away than it looks.
Meltemi season: when it blows
Roughly May or June to September, with the strongest and most frequent episodes in July and August. Early in the season the episodes are shorter and lighter, with longer gaps between them. In high summer there can be a week or more of strong wind with barely a pause, and a few days of force 7 gusting 8 is nothing unusual. By late September the gaps are longer again and the first autumn weather starts to take its place.
For anyone planning a charter or a cruise, this matters more than any other fact about Aegean weather. June and September show you the meltemi’s good side more often than its bad one. Late July and August are when you are most likely to spend a day or two in harbour waiting for it to ease.
Meltemi direction around the Aegean
The wind follows the shape of the sea and the land around it, so its direction swings as it goes south.
| Area | Usually from | What to expect |
|---|---|---|
| North Aegean, Chalkidiki, the Sporades | Northeast | A long stretch of open water, so the sea builds through the day |
| The Cyclades | North | The heart of it: the strongest and most persistent, accelerated in the channels |
| Dodecanese and the Turkish coast | Northwest | Strong gusts off the high islands and peninsulas |
| Saronic and Argolic gulfs | North to northeast | Partly sheltered by the land; often lighter |
| Crete | North to northwest | Gusts down the valleys on the south coast |
These are the usual directions, not rules. Local land bends the wind further, and on any given day a headland can turn a northerly into a northwesterly within a mile.
How strong the meltemi blows, and when in the day
On an ordinary meltemi day expect force 5 or 6 in the open, force 7 in a strong episode and occasionally 8. In the channels and off the capes, add a force. An episode can last from a couple of days to more than a week.
Most days have a rhythm. Mornings are often light or moderate. The wind fills in from late morning, blows hardest in the middle and late afternoon, and eases in the evening, sometimes to almost nothing by midnight. Part of the reason is daytime heating, which stirs the air and brings the stronger wind from a few hundred metres up down to the water. At night the lowest layer of air settles and the wind at sea level drops.
A strong meltemi ignores the rhythm and blows straight through the night. If it is still blowing hard at midnight, assume the episode is not over, and do not count on a calm dawn for tomorrow’s passage.
Acceleration zones and gusts off the islands
The forecast for the central Aegean is a fair average. The wind you actually meet depends on exactly where you are, and in the meltemi the differences are large.
Between islands the wind is squeezed and speeds up. The Kafireas strait, the Cavo Doro channel between the southern tip of Evia and Andros, is the best known: a meltemi that is force 6 in the open can blow 7 or 8 through the strait, a current runs through it as well, and the sea there is short, high and confused. Plenty of skippers go through it early in the morning or not at all on a strong day. The same thing happens on a smaller scale in the channels between Andros, Tinos and Mykonos, between Paros and Naxos, and off the ends of long capes such as the tip of the Datça peninsula on the Turkish side.
In the lee of high islands comes the opposite surprise. You tuck in behind an island for shelter from the sea, and the wind comes over the ridge and down the slopes in gusts far stronger than the wind outside: dark patches racing across the water toward you, the boat heeling hard at anchor, then a minute of near calm before the next one. The south coast of Ikaria, under a ridge of about 1,000 m, is notorious for it, and so is the south coast of Crete. Any island with a ridge of a few hundred metres can do it on a strong day.
Shelter from the sea is not shelter from the wind. Anchor in those bays in sand rather than weed, with plenty of chain, and expect a busy night. Our pieces on how much chain to let out and choosing an anchorage go into the detail.
Sailing Greece in the meltemi: planning passages
The old advice holds: go south with it, and make your northing early.
Across a whole cruise, that means arranging the route so the long legs run south or southeast with the wind aft of the beam. It is the logic behind the one-way charters that run from north to south. If you have to come back north, put that leg where a lull is forecast between episodes, and keep spare days in hand, so a strong episode cannot pin you against a flight home.
On the Turkish coast the same logic runs from northwest to southeast. From Bodrum south and east toward Datça, Marmaris and Göcek the meltem is behind you, and the return trip is the leg to plan around: early starts, short hops, and patience.
Within a single day, it means leaving early. The morning is lighter more often than not, so any leg with the wind forward of the beam goes at first light, and the exposed channels get crossed before 11:00. By early afternoon you want to be anchored or moored, which in a busy harbour is also when the last berths go.
Look at the sea as well as the wind. A few days of meltemi build a short, steep sea of a couple of metres or more in the open central Aegean, and in the channels it stacks up and breaks. A cruising boat that sails upwind at 6 knots in flat water will do well to make 3 knots toward her destination in that. Off the wind the same sea gives fast, rolling sailing, but a breaking crest under the quarter can broach a boat carrying too much sail, so reef for the gusts even when the run feels easy.
Anchorages and harbours in a meltemi
Choose bays that open to the south with land to the north, then look at how high that land is. A low headland gives shelter from both wind and sea. A high one gives shelter from the sea and sends the gusts down on you. Sand holds best against the snatching loads of a gusty night; Posidonia and weed are poor holding when the gusts start yanking the bow round.
Harbours need the same thought. Some island harbours face north and take a surge in a strong meltemi; the pilot book will tell you which. Many quays lie so that the meltemi blows straight across the berths, which turns mooring stern-to into a crosswind exercise with gusts. Arrive in the morning, before the wind builds and before the harbour fills, and lay your anchor well upwind. Our step by step guide to Med mooring stern-to covers the crosswind technique.
At night a strong meltemi tests every anchor in the bay, and the boats upwind of you are the ones that will drag down onto you. Set your anchor hard, let out more chain than you think, and keep an anchor alarm running.
What the forecasts get right, and what they miss
The models handle the meltemi itself well. It is a large-scale pattern, a high and a low far apart, and global models see that kind of thing coming days ahead. The start and end of an episode and its general strength are usually right three or four days out, and ECMWF, GFS and ICON tend to agree on it. Our comparison of ECMWF, GFS and ICON explains how to read them together.
What they miss is the local detail. The channels between the Cyclades are a few miles wide, narrower than the models can draw properly, and the island ridges are smoothed down in the model’s version of the land. So the acceleration through the Kafireas strait and the gusts off Ikaria are mostly missing from the numbers. Our rule of thumb: in the channels and off the capes, add a force to the model’s mean wind; in the lee of high islands, expect gusts well above the forecast gust.
Read the Greek national forecast as well. The Hellenic National Meteorological Service gives the wind in Beaufort forces for each sea area, and its forecasters know where to write “locally 8”.
Planning a week in high summer
Plan a week in July as if the meltemi will blow force 6 for four days of it. Put the longest leg downwind. Put the one leg that has to go north on a dawn start, ideally on a day the models show as a lull. Keep a spare day at the end, so you never have to beat back to base against a deadline. If the meltemi turns out kinder than that, the spare day becomes a lazy one in a bay of your choosing.